Tank filling system and method

ABSTRACT

A tank filling system comprising a first filling coupler that couples to a first set of fittings disposed at a first tank end of a tank; a second filling coupler that couples to a second set of fittings disposed at a second tank end of the tank; a fluid source; a set of fluid lines and one or more fluid valves that communicate fluid from the fluid source to the first and second filling couplers; and a computing device configured to control the one or more fluid valves. In some examples, the tank can comprise an elongated folded tank having a plurality of elongated rigid tubing portions having a first diameter, a plurality of connector portions having a second diameter that is smaller than the first diameter and flexible corrugations and a rigid cuff, and taper portions disposed between and coupling successive tubing portions and connector portions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a non-provisional of and claims priority to U.S.Provisional applications entitled “FAST-FILL TANK SYSTEM AND METHOD” and“TANK FILLING SYSTEM AND METHOD” and respectively having applicationnumbers 62/479,699 and 62/620,935 respectively filed Mar. 31, 2017 andJan. 23, 2018. These applications are hereby incorporated herein byreference in their entirety and for all purposes.

This application is related to U.S. application Ser. No. 13/887,201filed May 3, 2013; U.S. application Ser. No. 14/172,831 filed Feb. 4,2014; U.S. application Ser. No. 15/183,614 filed Jun. 15, 2016; U.S.application Ser. No. 14/624,370 filed Feb. 17, 2015; U.S. applicationSer. No. 15/368,182 filed Dec. 2, 2016; U.S. application Ser. No.15/792,090 filed Oct. 24, 2017; U.S. Application Ser. No. 62/479,598filed Mar. 31, 2017; U.S. Application Ser. No. 62/479,699 filed Mar. 31,2017. These applications are hereby incorporated herein by reference intheir entirety and for all purposes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1a and 1b illustrate side views of a bare liner comprising a bodyhaving connector portions, taper portions and tubing portions.

FIG. 1c illustrates a close-up side view of corrugations of connectorportions of a bare liner.

FIG. 1d illustrates a close-up side view of corrugations of tubingportions of a bare liner.

FIG. 2a illustrates a side view of a bare liner bending via corrugationsof the connector portions.

FIG. 2b illustrates a side view of the liner of FIG. 2a covered withbraiding.

FIG. 3 illustrates a side view of a bare liner comprising a body havinga connector portion with a cuff and corrugations, a taper portion andtubing portion.

FIG. 4 illustrates one embodiment of a tank that is folded and held in astacking architecture defined by a plurality of transverse planks thatengage with a plurality of lateral planks.

FIG. 5 illustrates a cutaway side view of a set of fittings coupled toan end of a tank.

FIG. 6 is a diagram of a tank filling system in accordance with anembodiment.

FIG. 7 is a block diagram of a method of filling a tank with fluid inaccordance with one embodiment.

FIG. 8 illustrates an example tank having one hundred and twelvechambers in accordance with one embodiment.

FIG. 9a illustrates parameters of a conventional tank used in asimulation study performed for the tank shown in FIG. 8.

FIG. 9b illustrates four cases used to perform a 3D and 1D simulation.

FIG. 10 is a plot of average tank temperature over time for thesimulations.

FIG. 11 is a table of data obtained in the simulations.

FIG. 12 is a plot of average chamber temperature over time with noprecool.

FIG. 13 is a plot of last chamber temperature over time.

FIG. 14 is a schematic showing a Venturi assembly connected to a6-chamber tank, circulating gas flow during the filling of an example6-chamber tank with fluid.

FIG. 15 is a schematic showing the Venturi assembly of FIG. 14circulating the flow during the filling of a tank with fluid.

FIG. 16 is a schematic showing a tank having i+3 chambers.

FIG. 17 is a block diagram of a tank filling system in accordance withanother embodiment.

It should be noted that the figures are not drawn to scale and thatelements of similar structures or functions are generally represented bylike reference numerals for illustrative purposes throughout thefigures. It also should be noted that the figures are only intended tofacilitate the description of the preferred embodiments. The figures donot illustrate every aspect of the described embodiments and do notlimit the scope of the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning to FIGS. 1a-d , a bare liner 100A is shown as comprising a body105 having connector portions 110, taper portions 125 and tubingportions 130. The connector portion 110 can be corrugated, which canallow the connector portion 110 to be flexible such that the liner 100can be folded into a housing 300 as illustrated in FIGS. 3a and 3b .Non-corrugated portions 120 can be rigid in various embodiments.

In various embodiments, the connector portion 110 can have a diameterthat is smaller than the tubing portions 130, with the taper portion 125providing a transition between the diameter of the connector portion 110and the tubing portion 130. However, further embodiments can comprise aliner 100 with portions having one or more suitable diameter, and infurther embodiments, a liner 100 can have portions that arenon-cylindrical, which can include various suitable shapes. Theconnector portion 110 can comprise connector corrugations 111, which canallow the connector portion 110 to be flexible (e.g., as illustrated inFIGS. 2a and 2b ) such that the liner 100 can be folded into a housing300 as illustrated in FIGS. 3a and 3 b.

Additionally, as illustrated in FIGS. 1a, 1b, 2a and 3 the connectorportion 110 can comprise a cuff portion 115 defined by a non-corrugatedportion 120 or rigid portion of the connector portion 110 between thecorrugations 111 of the connector portion 110 and the taper portion 125.In further embodiments, the cuff portion 115 can be various sizes asillustrated in FIGS. 1a, 1b, 2a and 3. More specifically, FIGS. 1a and1b illustrate a cuff portion 115 being smaller compared to the cuffportion 115 illustrated in FIGS. 2a and 3. In some embodiments, the cuffportion 115 can have a length that is less than, equal to, or greaterthan the length of the taper portion 125. In some embodiments, the taperportion 125 can have a length that is less than, equal to, or greaterthan the length of the cuff portion 115 or twice the length of the cuffportion 115.

Similarly, in some embodiments, the tubing portions 130 can comprisecorrugations 131. However, in further embodiments, the corrugations 131can be absent from the tubing portions (e.g., as illustrated in FIG. 2a). Non-corrugated portions 120 can be rigid in various embodiments.

In one embodiment, the liner 100 can be generated via extrusion moldingsystems or the like, which can comprise rotating dies that areconfigured to rotate in concert such that corresponding dies mate aboutan extruded tube generated by an extruder. Corresponding mated dies canthereby define one or more of the connector portion 110, taper portion125 and/or the tubing portion 130.

In various embodiments, a vacuum can pull the material of an extrudedtube to conform to negative contours defined by the mated die. In someembodiments, positive pressure can be introduced within the tube toconform to negative contours defined by the mated die. In variousembodiments, such a manufacturing process can be beneficial becauseliners 100 can be made seamlessly, with no welds, and using a singlematerial.

In some embodiments, liners 100 having varying lengths of the connectorportion 110, taper portion 125 and/or the tubing portion 130 can be madeby selectively choosing the order of dies such that desired portions aremade longer or shorter. For example, in some embodiments, a liner 100can be produced that fits into an irregular or non-rectangular cavity,which can require a liner 100 to have tubing portions 130 of variablelengths.

In some embodiments, a liner 100 can be made by forming various piecesof the liner 100 and then coupling the pieces together. For example,connector portion 110 can be manufactured separately from the taperportion 125 and/or the tubing portion 130, and/or the cuff portion 115.Such separate portions can be subsequently coupled together to form theliner 100.

A liner 100 can comprise various suitable materials including plastic,metal, or the like. In some preferred embodiments, a liner 100 cancomprise Ultramid PA6, Rilsamid PA12, Lupolen HDPE, or the like.

Accordingly, the embodiments of a liner 100 shown and described hereinshould not be construed to be limiting on the wide variety of liners 100that are within the scope and spirit of the present invention. Forexample, liners 100 as described in U.S. Provisional Patent ApplicationNo. 62/175,914, which is incorporated herein by reference, illustratesome further example embodiments of liners 100.

In some embodiments, a liner 100 can be a naked liner 100A asillustrated in FIGS. 1a-d, and 2a . However, as illustrated in FIG. 2b ,in some embodiments a liner 100 can be a covered or over-braided liner100B, which can include a braiding 200 or other suitable covering. Anover-braided liner 110B can be desirable because the braiding 200 canincrease the strength of the liner and thereby increase the dutypressure under which the liner 100 may safely operate. Additionally,braiding 200 can be disposed in a plurality of layers in variousembodiments. For example, in one preferred embodiment, the braid 200 cancomprise six layers of 48 carrier carbon braid 200.

As discussed in detail herein, the material(s), shape, size,configuration and other variables related to a braid 200 can be chosento increase the strength provided by the braiding 200, increase theflexibility of the braiding 200, increase the strength to weight ratioof the braiding, and the like. In various preferred embodiments,braiding 200 can be configured to completely cover a liner 100. In otherwords, one or more layers of braiding 200 can be configured to cover theliner 100 such that the liner is not visible through the braid 200 onceapplied to the liner 100 and such that gaps between the braid are notpresent such that the liner 100 is visible through the braid 200.

In various embodiments, the tank 100 can be folded into athree-dimensional structure. For example, FIG. 4 illustrates oneembodiment where an over-braided liner 100B is folded and held in astacking architecture 405. The tank 100 can also include fittings 410disposed at ends 415 of the tank 100. More specifically, a first fitting410A can be coupled at a first end 415A of the tank 100 and a secondfitting 410B can be coupled at a second end 415B of the fitting.Although FIG. 4 illustrates fittings 410 coupled to the connectorportion 110 of the tank 100, in further embodiments, fittings can becoupled at any suitable portion of the tank 100, including the cuffportions 115, taper portions 125 and/or tubing portions 130. Suchfittings 410 can include crimp fittings, bolt fittings, or any othersuitable type of fitting. Examples of fittings in accordance with someembodiments are shown and described in U.S. patent application Ser. No.15/792,090 entitled FITTINGS FOR COMPRESSED GAS STORAGE VESSELS, filedOct. 24, 2017, which as discussed above is incorporated herein byreference in its entirety for all purposes.

In various embodiments, such fittings 410 can be configured to interfacewith a tank valve and have a hollow center bore that is not only largeenough to allow the passage of a fluid but also large enough to allowthe pass-through of valve instrumentation, or the like. For example, invarious embodiments, such tank valves can be instrumented to detect tankconditions within the tank 100, including temperature, pressure, or thelike, as described in more detail herein.

In some embodiments, a tank 100 can comprise smooth cuffs 115 at one orboth ends 415 of the tank 100 for fitting attachment (e.g., asillustrated in FIGS. 2a and 3, but with the corrugated portion 105removed). In some examples, connector portions 110 can comprise cuffsections 115 and corrugation sections 105 to allow for a smoothattachment surface for crimp fittings 410. However, in furtherembodiments, with modification to tooling mold blocks or the like, it ispossible to incorporate cuff sections 115 to the end sections 415 of thetank 100, leaving internal connector portions 110 completely corrugated.Such cuff sections 115 at ends 415 of the tank 100 can be varioussuitable diameters, which can be the same size as, larger than, orsmaller than internal connector portions 110, and such connectorportions 110 can be completely or partially corrugated. In other words,some embodiments can include repeating tank geometries for internalportions of the tank 100 between the ends 415, with a different tankgeometry on the ends 415 of the tank 100. Non-periodic tank geometriescan be generated in various suitable ways including a liner formingmachine with swappable mold blocks as discussed herein, or the like.

Turning to FIG. 5, fittings 410 can be configured to couple with ends415 of a liner 100. In some embodiments, fittings 410 can be configuredto couple with an over-braided liner 100B that includes a liner 100,which is surrounded by one or more layer of braiding 200 as illustratedin FIG. 5. For example, fittings 410 can comprise a stem 520 and aferrule 540, which are configured to couple with an end 415 of a liner100 that is surrounded by one or more layer of braiding 200 as describedin detail herein.

Fittings 410 can be made of various suitable materials including metal,plastic, or the like. In some embodiments, fittings 410 can beconfigured to be in contact with compressed hydrogen and can beconfigured to be resistant to hydrogen embrittlement or weakening of thefittings 410 and fracturing resulting from hydrogen diffusion into thefittings 410. For example, the fittings 410 can comprise a materialand/or surface coating that is resistant to hydrogen induced fracturing.

The stem 520 can define a bore 521 that extends through the stem 520along an axis X between a first and second end 522, 523. In someembodiments having a larger diameter bore 521 can be desirable toincrease the flow rate through the bore 521, which can be desirable forfaster filling. Additionally, a larger diameter bore 521 can bedesirable for allowing sensors to be inserted into the bore 521 and intothe interior cavity 505 defined by the liner 100.

The stem 520 can comprise a head 524 that includes threads 525, whichcan be configured to couple with various systems such that suitablefluids can be introduced to and/or removed from an interior cavity 505defined by the liner 100 as described in more detail herein. Forexample, where such a fluid comprises hydrogen, the head 524 can bedirectly or indirectly coupled with a hydrogen filling station to fillthe interior cavity 505 defined by the liner 100 with hydrogen and canbe directly or indirectly coupled with a vehicle engine to providehydrogen fuel to the vehicle engine from hydrogen stored within theinterior cavity 505 defined by the liner 100.

The head 524 can also connect to various other suitable componentsincluding a valve, pressure regulator, thermally activated pressurerelief device, temperature sensor, pressure sensor, or the like. Whilevarious example embodiments discussed herein relate to a male conicalshape of a head 524 that can be configured to seal against acorresponding female cone, further coupling or mating structures ofvarious configurations can be implemented in further embodiments. Forexample, in one embodiment, the head 524 can comprise an O-ringface-seal, an O-ring bore-seal, or the like.

Additionally, various components can be configured to extend into afitting 410 or into the cavity 506 defined by the over-braided liner100B. For example such components can include at least a portion of agas injector, a gas receiver (e.g., including a filter and an excessflow valve), a temperature sensor, a pressure sensor, a bleed valve, atemperature pressure relief device (TPRD), and the like. In someembodiments such components can be inserted into and reside within thebore 521 of the stem 520 and/or within the cavity 505 defined by theliner. In various embodiments, it can be desirable to have a largediameter bore 521 to accommodate such components.

The head 524 can extend to a coupling architecture 528 defined by afirst and second rim 529, 530 disposed on opposite sides of and defininga coupling groove 531. A coupling body 532 can extend from the couplingarchitecture 528 and terminate at the tip 533 disposed at the second end523 of the stem 520.

The ferrule 540 can comprise a cylindrical body having a first andsecond end 541, 542 with a lip 544 defining a coupling orifice at thefirst end 541. The ferrule 540 can further define a cavity that extendsbetween the first and second end 541, 542 and opens to the couplingorifice at the first end 541 and an opening at the second end 542.

In various embodiments, the stem 520 and ferrule 540 can couple about anend 415 of an over-braided liner 100B in various suitable ways such thata fluid-tight seal is generated by the resulting fitting 410. Such acoupling can be configured or rated for use with pressurized fluidsincluding being rated for use at 10 MPa, 25 MPa, 50 MPa, 70 MPa, 90 MPa,110 MPa, 130 MPa, 150 MPa, or the like. In one preferred embodiment, afitting 410 comprising a stem 520 and ferrule 540 as described hereincan be rated for use with pressurized hydrogen at 70 MPa nominal workingpressure. In another preferred embodiment, a fitting 510 comprising astem 520 and ferrule 540 as described herein can be rated for use withcompressed natural gas (CNG) at 25 MPa nominal working pressure.Although various embodiments discussed herein can be configured for usewith fuel fluids such as hydrogen or CNG, further embodiments can beconfigured for use with any suitable fluid at various suitablepressures. Additionally, some embodiments can be configured for use withcryogenic fluids, room-temperature fluids, or heated fluids.

Turning to FIG. 6, a tank filling system 600 of one embodiment 600A isillustrated that comprises a control device 610 that drives a valveassembly 620 to direct fluid from a fluid source 630 to filling couplers640 via fluid lines 650. The filling couplers 640 are removably coupledto fittings 410 on ends 415 of a tank 100. More specifically, a firstfilling coupler 640A is removably coupled to a first fitting 410A at afirst end 415A of the tank 100, and a second filling coupler 640B isremovably coupled to a second fitting 410B at a second end 415B of thetank. The control device can be operably connected to the fillingcouplers 640 as described in more detail below.

The filling couplers 640 can be removably coupled to the fittings 410 invarious suitable ways. For example, referring to the example fittings410 of FIG. 5, filling couplers 640 can couple with the threads 525 onthe head 524 of the stem 520, which can provide a fluid-tight sealbetween the filling coupler 640 and the fittings 410. Additionally, invarious embodiments, the filling couplers 640 can comprise one or moresensors, which can include a temperature sensor, pressure sensor,velocity sensor, and the like. When a filling coupler 640 is coupledwith a fitting 410, such sensors can be disposed within the body of thefilling coupler 640, and can extend into and be disposed within thefittings 410 (e.g., within the bore 521) or within a portion of the tank100 (e.g., the cavity 505).

The control device can comprise any suitable computing system orcomputing device, which can receive data from one or more sensorsassociated with the fitting couplers 640, tank 100 or the like, viawired and/or wireless communication. The control device 610 can controlthe one or move valves 620 to control flow of fluid from the fluidsource 630 to the ends 415 of the tank 100 via the fluid lines 650.Although one example configuration of valves 620 is illustrated in FIG.6, it should be clear that any suitable configuration of one or morevalves, or the like, is within the scope and spirit of the presentdisclosure, and the example configuration of FIG. 6 should not beconstrued to be limiting. For example, the illustration of FIG. 6 shouldnot be construed to exclude configuration having valves collocated atthe fluid source 630, fitting couplers 640, or the like.

Pressurized gaseous fuel tanks can experience heating when filled due toheat of compression and, for some gasses, to the Joule-Thompson effect.For safety, some compressed fuel filling stations control the fillingrate to avoid dangerously high temperatures. In addition, the hightemperatures can be undesirable because they can result in low densityat a given pressure, thus requiring overpressure to reach the targetdensity (state of charge near 100%) or under-filled tanks.

Such heat generation can therefore result in undesirably long fillingtimes that take longer than filling gasoline or diesel fuel tanks and/orunder-filled tanks. To mitigate these issues associated with gaseousfuel tanks, many stations have the option of gas pre-cooling. With gaspre-cooling, the gas is cooled to a low temperature (e.g., as low −40°C.) before the gas enters the tank. This has the effect of lowering themaximum temperature that the gas reaches due to heat of compression,since the initial temperature is lower.

Gas pre-cooling can add significant additional complexity to theconstruction of fueling stations, which can undesirably increase capitalcost and operational cost for the fueling station. This increased costmay be transferred to the customer in the form of higher gas prices. Inaddition, pre-cooling components can have poor reliability in someexamples, resulting in significant station downtime and additional costdue to maintenance and replacement parts.

Novel conformable tanks discussed herein and in related applications(e.g., U.S. Ser. No. 13/887,201; U.S. Ser. No. 14/172,831; U.S. Ser. No.14/624,370; U.S. Ser. No. 15/183,614; and U.S. Ser. No. 15/368,182,which are hereby incorporated herein by reference) can be advantageousover conventional monolithic compressed gas tanks because theconformable shapes can have more surface area per unit volume ofstorage. Such increased surface area can allow for more rapid heatdissipation, which can increase fast-fill performance. In addition, suchconformable tanks can have a smaller cross-sectional area, which canresult in higher flow velocity during filling and hence betterconvective heat transfer from the gas to the tank wall (i.e., higherNusselt number).

During filling or fast-fill, such novel pressure vessels can reach alower average temperature than conventional pressure vessels. This canbe because such novel pressure vessels have a higher ratio of surfacearea to volume, and because the gas can have a higher average speed dueto the smaller tank diameter, resulting in greater convective heattransfer. This can result in a reduced need for gas pre-cooling.Conformable pressure vessels can thus be filled with fluid that isprecooled to a higher temperature or not precooled at all, while stillachieving the filling speeds that are normally associated withpre-cooled gas.

However, in some embodiments, less mixing can occur during the fillingof various example tanks 100 or pressure vessels due to their elongatedshape, meaning that the difference between maximum and minimumtemperature at the end of a filling can be much more extreme than forother configurations of pressure vessels. In particular, the gastemperature near the ends 415 can remain close to the temperature of theinflowing gas, since the flow speed at the ends 415 can result in goodheat transfer to the walls. The chambers of the tank 100 that are farfrom the ends 415, on the other hand, can heat up considerably becausethere is little flow in the far region of the tank 100 and hence havepoor convective heat transfer.

Such a temperature rise at one end 415 of the tank 100 in suchembodiments can be mitigated by filling from alternating ends 415A, 415Bof the tank 100. For example, at the start of fill, the tank 100 can befilled from the first end 415A, and the temperature at the second end415B can rise. When the temperature at the second end 415B reaches adefined high value, the inlet to the first end 415A can be closed, andthe inlet to the second end 415B can be opened. Thus, in variousembodiments, the end 415 that is hottest can be given a high flowvelocity and can dump heat to the walls of the tank 100. This patterncan be repeated until the tank 100 is filled. The frequency of flowswitching can be chosen so that the fluid temperature of the tank 100stays below a target maximum temperature.

Turning to FIG. 7, a block diagram of method 700 of filling a tank 100with fluid in accordance with one embodiment is illustrated. The method700 begins at 705, where a first fitting coupler 640A is coupled with afirst fitting 410A at a first end 415A of a tank 100 (e.g., see FIG. 6).At 710, a second fitting coupler 640B is coupled with a second fitting410B at a second end 415B of the tank 100.

The method 700 continues to 715, where filling of the tank 100 withfluid at the first end 415A is initiated. For example, referring to theexample tank filling system 600 of FIG. 6, the tank 100 can be filledwith fluid from the fluid source 630 by the control device 610 actuatingone or more of the valves 620 such that fluid from the fluid source 630travels via a fluid line 650 to the first fitting coupler 640A, wherethe fluid enters the first fitting 410A and enters the first end 415A ofthe tank 100. In some examples, filling can be initiated by a useractuating a button associated with the tank filling system 600 and thecontrol device 610 can confirm suitable coupling between the fittingcouplers 640 and fittings 410 before initiating filling at the first end415A.

Returning to the method 700, at 720 a determination is made whetherfilling is complete. For example, in various embodiments a fill statusof the tank 100 can be determined based at least in part on data fromone or more sensors associated with the tank 100 and/or fitting couplers640. In one example, one or both of the fitting couplers 640 can includea pressure sensor that determines a pressure of fluid within the tank100, which can be used to determine a fill state of the tank 100. Inother words, one or more pressure sensors can be used to determinewhether the tank 100 is full or at a filling threshold based at least inpart on a determined pressure of the tank 100.

If at 720 filling is not complete, then the method 700 continues to 725,where a determination is made whether a temperature of the first end415A of the tank 100 has reached a threshold. For example, in variousembodiments, the first fitting coupler 640A can comprise a temperaturesensor that can sense a temperature at the first end 415A of the tank100. Temperature thresholds can be any suitable temperature threshold,including a maximum temperature threshold of 85° C. However, in furtherembodiments, such a maximum threshold can include 60° C., 70° C., 80°C., 90° C., 100° C., and the like.

If at 725 a temperature at the first end 415A has not reached thetemperature threshold, then the method 700 cycles back to 715, wherefilling of the tank 100 at the first end 415A continues. However, if atemperature at the first end 415A has reached the temperature threshold,then at 730, filling of the tank 100 at the first end 415A is stopped,and at 735, filling of the tank 100 at the second end is initiated. Forexample, the control device 610 can receive temperature readings fromone or more temperature sensors associated with the first fittingcoupler 640A and determine whether the temperature at the first end 415Ahas reached the temperature threshold. The control device 610 cancontrol the one or more valves 620 to maintain filling at the first end415A or to stop filling at the first end 415A and begin filling at thesecond end 415B.

Returning to the method 700, at 740, a determination is made whetherfilling is complete, and if not, the method 700 continues to 745 where adetermination is made whether a temperature at the second end 415B hasreached a temperature threshold. If not, the method 700 cycles back to735, where filling at the second end 415B is maintained. However, whereit is determined that a temperature at the second end 415B has reached atemperature threshold, then the method 700 continues to 750, wherefilling at the second end is stopped, and then at 715, filling of thetank 100 at the first end is initiated.

As shown in the example method of FIG. 7, filling can alternate betweenthe first and second ends 415A, 415B until it is determined that fillingis complete at 720 or 740. For example, where the control device 610obtains data from one or more sensors associated with the tank 100,filling couplers 640, or the like, that indicates that the tank 100 isfull or at a filling threshold, then filling at the first and/or secondends 415A, 415B can be terminated to stop filling at 799. The first andsecond filling couplers 640A, 640B can then be removed from the firstand second fittings 410A, 410B at the first and second ends 415A, 415Bof the tank 100.

In various examples, any of the steps or operations of the method 700 ofFIG. 7 can be performed automatically and without human intervention.For example, the control device 610 can, beginning at 715, initiatefilling of the tank 100; determine whether filling of the tank iscomplete, switch filling between ends 415; maintain filling at an end415; determine whether a temperature at the ends 415 has reached orexceeded a temperature threshold; and stop a filling session at 799. Infurther examples, coupling and/or de-coupling of the filling couplers640A, 640B can also be automated, including via an automated dockingstation, robotic arm(s), and the like.

A simulation study was performed comparing one example of a tank 100B asshown in FIG. 8 to a conventional tank having the parameters illustratedin FIG. 9a . A 3D simulation for the example tank 100B (5 kg having onehundred and twelve tubing portion chambers 130) was performed for thefour cases illustrated in FIG. 9b , and a 1D simulation was performedfor the conventional tank for the same four cases illustrated in FIG. 9b.

Each of the test cases included:

20° C. ambient temperature, 30° C. “hot soak”0.5 MPa initial pressure

21.8 MPa/min., as per SAE J2601

H70-T40 (−33° C. pre-cool)Fill time of 3.1 minutes to 67.9 MPa

NOTE: In some embodiments, no standard exists for 0° C. pre-cool or nopre-cool, but the 70-T20 specification allows for −17.5° C. pre-cool.This can require 6.7 MPa/min. for a 9.9 minute fill.

Plots of various results are illustrated in FIGS. 10-13.

The results can illustrate the following for various embodiments of thenovel tank 100 compared to conventional tanks:

Increased surface area and flow velocity of novel tanks 100 can allowfor better heat transfer in various embodiments. Accordingly, pre-coolcan be unnecessary in such embodiments of tanks 100. In someembodiments, it can be desirable for materials to be designed forworking temperature of 120° C. However, if 120° C. working temperatureis not possible, filling from alternating ends can keep maximumtemperature well below 85° C., in accordance with some embodiments. Morespecifically, the 3D results show maximum temperatures at the lastchamber of 120° C. and 116° C., respectively. These temperatures arehigher than a limit of 85° C., but that limit applies only to theaverage temperature of the pressure vessel as a whole.

Additionally, the following was observed during these tests:

Flow rate is <3 g/s for 10-chamber tanks. For a 4.5 kg tank, requiredflow rate is −30 g/s for a 3-minute fill. Highest temperature is at thefar end of the tank, where gas is the most stagnant and, therefore, hasthe lowest heat transfer coefficient for transferring heat to the walls.For some tank sizes, peak temperature goes down as number of chambersgoes up—this can be because the flow rate goes up, so more heat istransferred to walls as gas is flowing. Initial gas in the tanks can bethe gas that hits peak temperatures, since this gas is not pre-cooledand has a low thermal mass due to low initial density. Tank pressure canbe nearly uniform throughout tank during fill—this surprising resultindicates that the flow resistance caused by the bends can benegligible.

In some examples, a challenge with tanks 100 is how to estimate thestate of charge (SOC) of a tank 100 during filling, if the difference intemperature from between the first and second ends 415A, 415B isextreme. The average density must be determined in some examples inorder to know the SOC, and to estimate the average density, twothermodynamic state variables can be required: the average pressure andthe average temperature. The simulations show very little deviation inpressure along the length of the tank 100, so the average temperature isthe only unknown in various examples.

In some embodiments it is possible to estimate density using temperatureat the non-filling end. Density can have a weak dependence ontemperature in the relevant range of temperatures. Therefore, thetemperature at the non-filling end of the tank can be used as areplacement for the average temperature when estimating the averagedensity. For example, a filling simulation with no precool ends whenP_(avg)=85 MPa and T_(avg)=83° C., yielding an average final density ofρ_(avg)=39.6 g/L. If instead the temperature of the last chamberT_(last)=116° C. were used, it would result in an estimated finaldensity of ρ_(avg)=37.2 g/L, which is only 6% off from the actual value.Note too that this can yield a conservative estimate, thereby ensuringthat the tank 100 will not be over-pressurized.

Some embodiments can estimate density using flux of gas during filling.Before filling, the initial density, ρ_(initial), can be estimatedaccurately in some examples since there may be minimal temperaturevariations within the tank 100. Given this value and the tank volume, V,the density can be estimated during filling by integrating the mass fluxinto the tank, {dot over (m)}(t). In hydrogen filling stations, forexample, it can be necessary in some embodiments to have an accurateestimate of the mass flux in order to charge the customer for fuel, sothis information may already be available. The average density can thenbe given by the equation

${\rho_{avg}(t)} = {\rho_{initial} + {\frac{\int_{0}^{t}{{\overset{.}{m}(\tau)}d\; \tau}}{V}.}}$

In another example, a fueling and defueling simulation of a 50-chamber,10 kg tank 100 was conducted to measure state of charge (SOC) of thetank. In various examples, it can be desirable to measure theinstantaneous (SOC) of a tank 100 during fueling and defueling of thetank 100 to within a certain accuracy, which entails measuring theaverage density to within a certain accuracy. In order to estimate theaverage density, and hence the SOC, the average pressure and averagetemperature in the tank 100 can be determined. In various examples,pressure deviations in the tank 100 can be considered minimal;therefore, it can be desirable to determine the average temperature.

In some examples, it can be challenging to determine the averagetemperature at the end of fueling for various reasons includingtemperature being least homogenous at the end of fueling. Additionally,pressure can be highest at the end of fueling, so incorrect temperaturemeasurements can lead to a large absolute error in density measurement.

In some embodiments, sensors (e.g., thermocouples or the like) can bedisposed at the first and second ends 415A, 415B of a tank 100 (e.g.,associated with fitting couplers 640). Accordingly, in various examples,such sensors we can be used to determine the SOC in the first and last(i.e., 50^(th)) chamber:

SOC₁=ρ(p,T ₁)/ρ(70 MPa,15° C.)

SOC₅₀=ρ(p,T ₅₀)/ρ(70 MPa,15° C.)

One way to determine the average SOC of the tank 100 includes averagingreadings from sensors at the first and second ends 415A, 415B of a tank100,

SOC_(tank)=(SOC₁+SOC₅₀)/2

However, in some examples, such a calculation may not produce anestimate that is accurate enough to meet a desired accuracy threshold.Since SOC_(tank) can be closer in value to SOC₅₀ than to SOC₁, analternative method of determining SOC_(tank) can include taking aweighted average of the readings from sensors at the first and secondends 415A, 415B of a tank 100, so that SOC₅₀ is weighted higher thanSOC₁,

SOC_(tank)=(α·SOC₁+SOC₅₀)/(1+α).

In various examples, α<1 can produce a desirable estimate of theSOC_(tank), since α<1 can result in a formula that weights the SOC ofthe chambers 130 at the terminal end 415B of the tank 100 more than thechambers 130 at the beginning end 415A.

During filling of an elongated and folded tank 100 with fluid, the fluidwithin the tank can exceed a maximum desired temperature limit locally,even if the average fluid temperature within the tank 100 stays belowsuch a desired maximum temperature limit. This can be due to the factthat there is limited mixing in some embodiments of such tanks 100,where the fluid at a non-filling second end 415B of the tank 100 heatsup due to having a low flow velocity (and hence low heat transfer) butis not able to mix with cool fluid near an inlet end 415A.

Various suitable temperature limits can be accommodated in accordancewith embodiments discussed herein. For example, vessel regulatorystandards (such as UN GTR 13, SAE J2579, SAE J2601) are written for amaximum gas temperature of 85° C. due to a maximum tank componenttemperature of 85° C. However, in further embodiments, a maximum gastemperature can include 60° C., 70° C., 80° C., 90° C., 100° C., and thelike.

In some embodiments, filling the tank 100 from alternating ends asdiscussed herein can result in lower maximum (as well as average)temperatures, due to various effects. For example, when the filling endis switched, the hot stagnant fluid at the non-filling end 415 of thetank 100 can be given a high flow velocity by filling, allowing thefluid to dump heat to the walls of the tank 100. In another example,when the filling end is switched, the cold incoming fluid can mix withthe hot fluid at the end that was formerly the outlet, helping todecrease the maximum temperature in that location.

In further embodiments, a Venturi nozzle (also known as an eductor or anejector) can be used to circulate fluid flow during the filling process,which can result in lower maximum (as well as average) temperatures ofthe fluid and/or tank 100 during filling. For example, FIG. 14 is aschematic showing a Venturi assembly 1400 circulating fluid flow duringthe filling of an example 6-chamber tank 100. FIG. 15 is a close upschematic showing the Venturi assembly 1400 circulating the flow duringthe filling of the tank 100.

The Venturi assembly 1400 is shown comprising a Venturi nozzle 1405 thatintroduces a flow of fluid to a Venturi chamber 1410. The mixing chamberof the Venturi 1410 is connected to an inlet 1415 that communicates witha first end 415A of the tank 100 and introduces fluid into the interiorcavity 505 of the tank 100. An outlet 1420 is shown coupled at a secondend 415B of the tank 100, with the outlet 1420 coupled with the Venturichamber 1410 that introduces a flow of fluid into the Venturi chamber1410 that originates from fluid leaving the second end 415B of the tank100.

As shown in FIG. 15, fluid can enter the Venturi assembly 1400 via theVenturi nozzle 1405 at an inlet pressure p_(fill) before acceleratingthrough the nozzle 1405 with diameter D_(noz), where the pressure dropstop p_(noz) due to the increased speed of the flow. The low pressuredraws in the fluid from the outlet 1420 of the tank 100, which entersthe Venturi chamber 1410 at a pressure p_(out). The two fluid streamsfrom the nozzle 1405 and outlet 1420 can mix in the Venturi chamber 1410and then exit the Venturi chamber 1410 via the inlet 1415 to enter thefirst end of the tank 100, at a pressure p_(in). In some embodiments,the Venturi assembly 1400 and tank 100 can be configured to operate witha maximum mass flow rate {dot over (m)}_(fill) of 60 g/s. In furtherembodiments, it can be desirable for a tank 100 and Venturi assembly1400 be configured for, and to be filled at, a maximum pressure ramprate of less than or equal to 28.5 MPa/min.

Use of a Venturi assembly 1400 can decrease the maximum temperatureduring filling in various ways. In one example, the flow at the secondend 415B of the tank 100, rather than being stagnant, can have a massflow rate {dot over (m)}_(out), which can enable better heat transferfrom the hot fluid to the walls of the tank 100. In another example,there can be less temperature variation overall throughout the tank 100,since the hot fluid at the second end 415B of the tank 100 can beremoved from the tank 100 via {dot over (m)}_(out), and mixed with thecold filling gas, {dot over (m)}_(fill). Then, the hot gas at the secondend 415B of the tank 100 can be replaced with cooler gas that is flowingfrom the inlet of the tank 1415.

In some embodiments, it can be desirable for the pumping pressure of thenozzle 1405 to be strong enough to generate a significant circulatingmass flow, {dot over (m)}_(out). In various examples, the amount ofcirculating flow, {dot over (m)}_(out), can be determined by a balancebetween the dynamic pressure drop in the Venturi valve and the pressuredrop through the tank 100 and connecting tubing 650. In furtherexamples, for a fixed Venturi nozzle geometry, the circulating mass flowrate, {dot over (m)}_(out), can be approximately proportional to thefilling mass flow rate, {dot over (m)}_(fill), and not dependent on theinstantaneous pressure, density, or temperature. In other words, ϕ={dotover (m)}_(out)/{dot over (m)}_(fill) is only a function of geometry andflow resistance (which is itself a function of geometry) in variousexamples.

In some embodiments, a smaller Venturi nozzle diameter D_(noz) can leadto a greater dynamic pressure drop and hence more circulation. However,the nozzle diameter D_(noz) can be limited by choking concerns. If thenozzle diameter D_(noz) is too small in some embodiments, the nozzle1405 will choke, restricting flow into the tank 100. This can cause thetank 100 to fill slower at low pressures and to speed up in filling rateonce the tank 100 fills enough to eliminate the choking condition. Then,the tank 100 may not reach a full state of charge at the end of filling.In some examples, it can be desirable to configure a Venturi assembly1400 having a nozzle diameter D_(noz)>16.5 mm. In further examples, itcan be desirable to configure a Venturi assembly 1400 having a minimumof 6 mm inner diameter for the Venturi nozzle 1405. In still furtherexamples, it can be desirable to configure a Venturi assembly 1400having a minimum of 2 mm, 3 mm, 4 mm, or 5 mm inner diameter for theVenturi nozzle 1405, or other suitable minimum diameter.

Additionally, it can be desirable to use a Venturi nozzle 1405 with avarying diameter, so that the nozzle diameter D_(noz) can be decreasedwhen choking is not a concern. For example, the nozzle diameter D_(noz)can be decreased once the tank 100 reaches a high enough absolutepressure and/or at high ambient temperature when the filling rate isslower.

In some embodiments, the ratio ϕ can be increased by increasing theinner diameter of corrugations 111 of a tank 100 (see e.g., FIGS. 1, 2 aand 3). In some examples, improved circulation can be obtained throughincreasing corrugation inner diameter while keeping the ratio ofcorrugation inner diameter to outer diameter constant, and while keepingthe ratio of corrugation outer diameter to chamber outer diameterconstant. In further examples, improved circulation can also be obtainedthrough increased corrugation inner diameter while keeping corrugationouter diameter constant.

In some embodiments, it can be desirable for tubing 650 that connectsthe second end 415B of the tank 100 to the Venturi chamber 1410 to be asshort and as wide as possible. In some examples, this can limitpotential tank designs by requiring the two ends 415 of the tank 100 tobe positioned near each other.

In further examples, the Venturi assembly 1400 can be placed directly atthe first end 415A of the tank 100 in order to minimize losses andmaximize circulation. In some examples, tubing 650 should only be usedto connect the second end 415B of the tank 100 to the Venturi suctionport.

FIG. 16 is a schematic showing a tank 100 having i+3 chambers 130. Invarious embodiments, increasing or decreasing the number of chambers 130in a tank 100 can change fluid circulation through a tank 100. Forexample, decreasing the number of chambers 130 can also increasecirculation through decreased flow resistance. This effect can be moreprominent for tanks 100 with smaller diameters of corrugations 111. Insome examples, additional chambers 130 can add a negligible amount offlow resistance for some tank geometries. While various embodiments canhave any suitable plurality of chambers 130, in some embodiments it canbe desirable to configure a tank 100 for a capacity of 7-10 kgregardless of the number of chambers 130.

In some embodiments, it can be desirable to split a tank into multipleunits. For example, splitting a tank into multiple units can increasethe amount of gas circulation, since the diameter of the Venturi nozzle1405 can be decreased due to less mass flow per tank, {dot over(m)}_(fill), being required.

In various embodiments, it can be desirable to make the Venturi nozzle1405 as small as possible so that Venturi nozzle 1405 provides as muchsuction pressure as possible without choking the flow. In furtherembodiments, it can be desirable to reduce the hydraulic resistance ofthe tank 100 (e.g., the tubing portions 130, connector portions 110, andthe like) as much as possible. For example, in some embodiments reducingthe hydraulic resistance of the tank 100 can be done by increasing thediameter of corrugations 105, making the connector portions 110 as shortand/or a wide as possible, and the like. In some examples, a purpose ofone or both of such elements can be to enable as high a ratio of {dotover (m)}_(out)/{dot over (m)}_(fill), as possible.

Also, while various embodiments discussed herein relate to introducingfluid into a tank 100, various embodiments can be employed similarlyduring defueling, which can limit the temperature variations in the tank100 during defueling and/or can reduce the temperature drop in the tank100 during defueling. Additionally, while some examples herein may bediscussed in relation to gas, in further embodiments any suitable fluidcan be used to fill a tank 100 or be held within a tank 100, includingone or both of liquids and gases. Also, while hydrogen gas storage tanksare discussed in some embodiments, any other suitable fluid fuel canfill and be held within a tank 100 in further embodiments, includingnatural gas, oxygen, methane, propane, acetylene, or the like.Additionally, some embodiments can include use of any suitable non-fuelgasses.

In various embodiments, the Venturi 1400 can be part of a passivefilling system that does not require control devices, temperaturesensors, and the like. In other words, in some examples, the fluid flowthrough the Venturi 1400 solely drives recirculation. However, infurther embodiments, the Venturi 1400 can include active control. Forexample one embodiment can include Venturi recirculation with a variablediameter of the Venturi nozzle 1405. Another embodiment can includeVenturi recirculation combined with end switching.

Turning to FIG. 17, a tank filling system 600 of another embodiment 600Bis illustrated that comprises a control device 610 that drives a valveassembly 620 associated with one or more Venturi 1400 to direct fluidfrom a fluid source 630 to filling couplers 640 via fluid lines 650. Thefilling couplers 640 can be removably coupled to fittings 410 on ends415 of a tank 100. More specifically, a first filling coupler 640A isremovably coupled to a first fitting 410A at a first end 415A of thetank 100, and a second filling coupler 640B is removably coupled to asecond fitting 410B at a second end 415B of the tank. The control device610 can be operably connected to the filling couplers 640 as describedherein.

The control device can comprise any suitable computing system orcomputing device, which can receive data from one or more sensorsassociated with the fitting couplers 640, tank 100, or the like, viawired and/or wireless communication. The control device 610 can controlthe one or move valves 620 to control flow of fluid from the fluidsource 630 to the ends 415 of the tank 100 via the fluid lines 650 andcontrol the flow of fluid from the ends 415 of the tank 100 to the oneor more Venturi assembly 1400. Although one example configuration ofvalves 620 and one or more Venturi assembly 1400 is illustrated in FIG.17, it should be clear that any suitable configuration of one or morevalves, one or more Venturi assembly, or the like, is within the scopeand spirit of the present disclosure, and the example configuration ofFIG. 17 should not be construed to be limiting.

For example, the illustration of FIG. 17 should not be construed toexclude a configuration of a filling system 600 having valves collocatedat the fluid source 630, fitting couplers 640, or the like. In anotherexample, a filling system 600 can include the configuration as shown inFIGS. 14 and 15 where a single Venturi assembly 1400 introduces fluid tothe first end 415A of the tank 100 with the second end 415B of the tank100 providing an outlet 1420 that feeds into the Venturi chamber 1405.

In some embodiments, the filling system 600 can be non-alternating. Inother words, the filling system 600 may not switch the filling end 415between the first and second ends 415A, 415B. Accordingly, in someembodiments, the first end 415A can remain the inlet 1415 and the secondend can remain the outlet 1420. However, in further embodiments, theinlet 1415 can switch between the first and second ends 415A, 415B withthe outlet 1420 similarly switching between the first and second ends415A, 415B. For example, the valves 620 can be configured to switch theinlet 1415 and outlet 1420.

In another example, the filling system can comprise a first and secondVenturi assembly 1400 that are respectively associated with first andsecond ends 415A, 415B with the first Venturi assembly 1400 having thefirst end 415A as the inlet 1415 and the second end 415B as the outlet1420. The second Venturi assembly 1400 can have the first end 415A asthe outlet 1420 and the second end 415B as the inlet 1415. In suchexamples, the valve(s) 620 can switch between the first and secondVenturi to switch filling from the first and second ends 415A, 415B.

Such switching of filling between the first and second ends 415A, 415Bhaving one or more Venturi can be achieved as discussed herein and asillustrated in FIG. 7, with the switching between the inlet filling end1415 also including switching of the outlet end 1420.

The described embodiments are susceptible to various modifications andalternative forms, and specific examples thereof have been shown by wayof example in the drawings and are herein described in detail. It shouldbe understood, however, that the described embodiments are not to belimited to the particular forms or methods disclosed, but to thecontrary, the present disclosure is to cover all modifications,equivalents, and alternatives.

It should be noted that the figures are not drawn to scale and thatelements of similar structures or functions are generally represented bylike reference numerals for illustrative purposes throughout thefigures. It also should be noted that the figures are only intended tofacilitate the description of the preferred embodiments. The figures donot illustrate every aspect of the described embodiments and do notlimit the scope of the present disclosure.

What is claimed is:
 1. A method of filling an elongated folded tankhaving a first and second end, the method comprising: coupling anelongated folded tank with filling system to a tank by: coupling a firstfilling coupler to a first set of fittings disposed at a first tank end;and coupling a second filling coupler to a second set of fittingsdisposed at a second tank end; wherein the elongated folded tank extendsbetween the first and second end and the elongated folded tank includes:a plurality of elongated rigid tubing portions having a first diameter,a plurality of connector portions having a second diameter that issmaller than the first diameter and having flexible corrugations and arigid cuff, and taper portions disposed between and coupling successivetubing portions and connector portions; introducing a first fluid flowinto the first end of the tank via the first filling coupler and thefirst set of fittings disposed at the first tank end; determining basedat least in part on first temperature data obtained from a firsttemperature sensor of the second filling coupler that a temperature atthe second end of the tank has at least reached a first threshold; basedat least in part on the determining that the temperature at the secondend of the tank has at least reached the first threshold, stopping thefluid flow into the first end of the tank via the first filling couplerand the first set of fittings disposed at the first tank end, andbeginning to introduce a second fluid flow into the second end of thetank via the second filling coupler and the second set of fittingsdisposed at the second tank end; determining based at least in part onsecond temperature data obtained from a second temperature sensor of thefirst filling coupler that a temperature at the first end of the tankhas at least reached a second threshold; based at least in part on thedetermining that the temperature at the first end of the tank has atleast reached the second threshold, stopping the second fluid flow intothe second end of the tank via the second filling coupler and the secondset of fittings disposed at the second tank end, and beginning tointroduce a third fluid flow into the first end of the tank via thefirst filling coupler and the first set of fittings disposed at thefirst tank end; determining that tank filling is complete; stopping anyflow to the first and second tank ends; de-coupling the first fillingcoupler from the first set of fittings disposed at the first tank end;and de-coupling the second filling coupler from the second set offitting disposed at the second tank end.
 2. The method of claim 1,wherein the determining that the temperature at the second end of thetank has at least reached a first threshold is performed by a computingdevice automatically without human interaction; wherein the stopping thefluid flow into the first end of the tank and the beginning to introducethe second fluid flow into the second end of the tank is generated bythe computing device automatically without human interaction; whereinthe determining that a temperature at the first end of the tank has atleast reached the second threshold is performed by the computing deviceautomatically without human interaction; and wherein the stopping thefluid flow into the second end of the tank and beginning to introduce athird fluid flow into the first end of the tank is generated by thecomputing device automatically without human interaction.
 3. The methodof claim 2, wherein the determining that tank filling is complete isperformed by the computing device automatically without humaninteraction.
 4. The method of claim 1, wherein the first and secondthreshold are the same temperature threshold.
 5. The method of claim 1,wherein the first threshold is a temperature of 85° C.
 6. The method ofclaim 1, wherein the first, second and third fluid flows comprisehydrogen.
 7. A method of filling a tank having a first and second tankend, the method comprising: introducing a first fluid flow into thefirst end of the tank via a filling coupler and a first set of fittingsdisposed at the first tank end; determining based at least in part onfirst temperature data obtained from a first temperature sensor of asecond filling coupler disposed at the second end of the tank that atemperature at the second end of the tank has at least reached a firstthreshold; based at least in part on the determining that thetemperature at the second end of the tank has at least reached the firstthreshold, stopping the fluid flow into the first end of the tank viathe first filling coupler and the first set of fittings disposed at thefirst tank end, and beginning to introduce a second fluid flow into thesecond end of the tank via the second filling coupler and a second setof fittings disposed at the second tank end; determining based at leastin part on second temperature data obtained from a second temperaturesensor of the first filling coupler that a temperature at the first endof the tank has at least reached a second threshold; and based at leastin part on the determining that the temperature at the first end of thetank has at least reached the second threshold, stopping the secondfluid flow into the second end of the tank via the second fillingcoupler and the second set of fittings disposed at the second tank end,and beginning to introduce a third fluid flow into the first end of thetank via the first filling coupler and the first set of fittingsdisposed at the first tank end.
 8. A computer implemented methodperformed automatically without human interaction, the method comprisingthe steps of claim
 7. 9. The method of claim 7, further comprisingcoupling a tank filling system to the tank by coupling the first fillingcoupler to the first set of fittings disposed at the first tank end andcoupling a second filling coupler to a second set of fitting disposed ata second tank end.
 10. The method of claim 7 wherein the tank extendsbetween the first and second end includes: a plurality of elongatedrigid tubing portions having a first diameter, a plurality of connectorportions having a second diameter that is smaller than the firstdiameter and having a flexible portion, and taper portions disposedbetween and coupling successive tubing portions and connector portions.11. The method of claim 7, wherein the tank is elongated and foldedbetween the first and second ends.
 12. The method of claim 7, furthercomprising: determining that tank filling is complete; and stopping anyflow to the first and second tank ends based at least in part of thedetermining that tank filling is complete.
 13. The method of claim 12,wherein the determining that tank filling is complete and stopping anyflow to the first and second tank ends occurs via a computing deviceautomatically and without user interaction.
 14. The method of claim 12,further comprising, after stopping any flow to the first and second tankends based at least in part of the determining that tank filling iscomplete, de-coupling the first filling coupler from the first set offittings disposed at the first tank end; and de-coupling the secondfilling coupler from the second set of fitting disposed at the secondtank end.
 15. The method of claim 7, wherein a Venturi assembly providesa fluid flow to the first filling coupler coupled to the first set offittings disposed at the first tank end; and wherein the Venturiassembly received a fluid flow from the second filling coupler coupledto the second set of fittings disposed at the second tank end.
 16. Atank filling system comprising: a first filling coupler that couples toa first set of fittings disposed at a first tank end of a tank; a secondfilling coupler that couples to a second set of fittings disposed at asecond tank end of the tank; a fluid source; a set of fluid lines andone or more fluid valves that communicate fluid from the fluid source tothe first and second filling couplers; a computing device configured tocontrol the one or more fluid valves.
 17. The tank filling system ofclaim 16, further comprising a Venturi assembly coupled to the set offluid lines and is configured to introduce an inlet fluid flow into thefirst filling coupler and into the first set of fittings disposed at thefirst tank end of a tank, the Venturi assembly further configured toreceive an outlet fluid flow from the second filling coupler that iscoupled to the second set of fitting disposed at the second tank end ofthe tank.
 18. The tank filling system of claim 16, further comprising afirst temperature sensor disposed at the first filling coupler and asecond temperature sensor disposed at the second filling coupler, andwherein the computing device receive temperature data from the first andsecond temperature sensor and controls the one or more fluid valvesbased at least in part on the temperature data from the first and secondtemperature sensor.
 19. The tank filling system of claim 16, wherein thefirst filling coupler is configured to be removably coupled to the firstset of fittings disposed at the first tank end of the tank; and whereinthe second filling coupler is configured to be removably coupled to thesecond set of fittings disposed at the second tank end of the tank.